DE 195 40 631 A describes an actuation device of an adjusting facility for automotive vehicle seats having a hand lever that is carried pivotal about an axis which is fixed with respect to the frame. Said lever is maintained in a central position by elastic means. A pivotal lever, which has two engagement regions, is pivotally hinged to the hand lever. An adjustment wheel that is provided with circumferential gear teeth is rotatably carried on the frame. The adjustment wheel is rotated in the one or in the other direction of rotation through the actuation movements of the hand lever. When the hand lever is actuated, the engagement region located in front in the direction of rotation moves into mesh with the gear teeth of the adjustment wheel, carrying it forward. Upon completion of the driving stroke, a control facility first causes the driving engagement region which is located in front in the direction of rotation to move away from the adjustment wheel, then the return stroke may take place. As a result thereof, the return stroke makes no rattling sound when an engagement region engaged with the teeth of the adjustment wheel is moved back. The two engagement regions are located in immediate proximity to each other; viewed from the axis of the output shaft, they are positioned at an angle of less than 90° to each other.
Such type actuation devices have basically proved efficient. The documents DE 44 00 910 A and EP 0 960 765 A describe similar actuation devices.
It is the object of the invention to improve the actuation device according to DE 195 40 631.1 in such a manner that it is simpler in construction and capable of taking higher manufacturing tolerances while still maintaining silent operation during the working stroke and the return stroke.